HighSensitivity DNA unexplained peack

[jasmineja]

We run PCR products of 800 and 1500 bp length after fragmentase treatment.
In order to be sure we have all the right fractions in the samples, we run the results with the High Sensitivity DNA assay before and after the adapters ligation. we are surprised to get a 160bp peack in all the samples after the ligation this peack did not appear before the adapter ligation, could it be some kind of adapter-adapter stuff? The adapter is around 30 bp so in the case of the “fork” conformation we should get a ~60 bp ligation product what could be the 160bp fragment ?

Ideas?

[EliG]

Hi Jasmineja,

I also observed such peaks around 160bp, but they are very little in height in my case. After PCR no such peaks are visible and we have no problems in sequencing the libraries.

I work only with 6µl of Adapters in the ligation-reaction in combination with 3µg starting-material.